Rotary casting machine for producing hollow rubber or like articles



CLES

3 Sheets-Sheet 1 D. G. REMPEL July 22, 1952 ROTARY CASTING MACHINE FOR PRODUCING HOLLOW RUBBER 0R LIKE'ARTI Filed Dec. 22', 1949 I REMPEL R m E G m H w R T E D ATTORNEY D. G. REMPEL July 22, 1952 ROTARY CASTING MACHINE FOR PRODUCING HOLLOW RUBBEROR LIKE ARTICLES Filed Dec. 22, 1949 3 Sheets-Sheet 2 I m T L t F m M w m. v 3 31:: I R a H m R H \.w i I I P m n ya a LP r uh u vn DH WA D \w m A Q O O 5% o 7 W N mm M v v z MW m a \& \w \NN \N \\N v \n? \w h MN I xxx L NIH L N 91 z {a IT H x ATTORNEY D. G. REMPEL July 22, 1952 ROTARY CASTING MACHINE FOR PRODUCING HOLLOW RUBBER OR LIKE ARTICLES Filed Dec. 22, 1949 5 Sheets-Sheet 3 INVENTOR. DIETRICH 6. REMPEL ATTORNEY aur Patented July 22, 1952 I 2,603,836 ROTARY CASTING MACHINE FOR PRODUC- ING HOLLOWRUBBER OR LIKE ARTICLES Dietrich G. Rempel, Akron, hio,-assigncr to Rempel Manufacturing, Inc., Akron, Ohio, a

corporation of Ohio' Application December 22, 1949, Serial No. 134,512

This invention relates to improved apparatus forproducing articles by deposition of flowable material in sectional cavity molds.

This application is a continuation in part of application, Serial No. 88,378, filed April 19, 1949 now-Patent 2,569,869.

The present invention is particularly adaptable for, carrying out the rotary casting process of said co-pending application, by which a plasterof-Paris-cavity mold containing a quantity of latex,.or similar aqueous dispersion material, is

5:Claims. (01.18526) rotated about a plurality of angularly disposed axes, to deposit the latex on the mold cavity surfaceportions, aided by capillary flow of water outwardlysthrough the mold pores.

object of the invention is to provide im provedmold-rotating apparatus, particularly usefill for connection with said rotary-casting pllocess, which is operable to applycompound rotaryimovement to a mold or molds about a plu rality of; axesewith smooth, steady actionthereon for attaining maximum uniformity of wall thicknessinthe products formed in the mold cavities. Another object of the invention is to provide mold-rotating apparatus of the class described including improved means for applying compound rotative, movement to a mold containing articleforming fluid in a manner which assures complete uniform coverage of; all portions of the mold cavity surfaces, including undercut portions thereof, and particularly overhanging, diflicultto-reach-wall portions-which might otherwise be missed because of the fluid falling from one cavityqportion to another by gravity. 7 Still another'object of the invention is to pro-. vide mold-rotating apparatus of the character described, wherein in the inoperative conditionof the same. a. mold-supporting unit is self -operating to be presented in convenient position for facilitatingrquick loading and. unloading the molds therefrom. a Z

Other objects of the invention will be manifest from the following brief description and the accompanying drawings.

Ofthe accompanying drawings;

Figure 1 is a side elevation, partly'broken away Figure 5 is a vertical cross-section taken substantially on the line 5-5 of Figure 2.

Figure 6 is a side elevation on a reduced scale, partly broken away and in section, illustrating 2 afinished-hollow rubber article produced in the rotary casting machine. f

Referring to Figures 1 to 5 of thedrawings, there is illustrated an improved machineparticularly adaptablefor practicing said rotary casting method, wherein a plurality of" mold rotating units 20 are each adapted to have removzably suppor-ted; thereon a plurality of stacked plaster-'of-Earis, sectional cavity molds 2|, each said unit 20 being operable toapplyia compound rotary movement tothe respective stack 22 y, Accordingly, supportingmembers or arms 2-3. of each of four such units 20' have hubs 23a; keyed or, otherwise fixed in the-respective ends of two shafts 24 and 25, which are eachsuitably journaled in spaced, horizontally; aligned bearing members 26 and-21 mounted on webs 28 and. 29extending vertically in parallel planes from a relatively fixedsupport 30. The shafts and 25 are rotated about the-parallel, horizontally extending axes thereof,-as by means of a common electrical power unit 32 throughendless chains 33 and 34 extendedbetween spaced'pinions 35 on thepower unit and relatively larger gears 36 and 31, fixed on the shafts 24 and 25 between-the spaced bearing members 26 and 2-! thereof. The units 2!] otherwise being similar in all respects, only one thereof will be described in detail and, therefore, like parts will be designated by like numerals.

The arm23 extends from its hub portion 23a at a substantial angleto the axis of the shaft. That is, the angularly extending arm is adapted to swing in a conical path with rotation of the shaft. Journaled in suitable-bearing means at the outer end of arm 23 is a spindle 38 which extends freely inwardly toward intersection with the axis of shaft 24, substantially at right angles to said angle of the arm. The molds 2 I are circular or disc-shaped and are centrally aper tured, as indicated at 39, for free sliding reception of spindle 38 therethrough, a stack 22 of such molds being adapted to be releasably clamped between a plate 40, fixed on the spindle at the inner end thereof adjacent the arm anda remov V able clamping plate 4! of a quickly releasable clampingdevice 42. Spacers 43 of relatively small size are positioned between the adjacent plaster molds of the stack to permit circulation of air for purposes to be described later. For counterbalancing the unit 20 with the molds stacked thereon, a pair of parallel rods 44' extending from hub 23a, in the same general angu lar direction as spindle 38, have a counterweight 45 slidably adjustable along the same. The weight 45 'is adjustable so that the loaded unit will be substantially dynamically balanced-forsmooth rotative operation thereof, but atthe same time so that when the machine is in stQppfid position the unit will always turn to the position thereof shown in Figures 1 and '2, that is, with the.

the axis of shaft 24 (or 25) although more or 1 less molds may be readily balanced in the unit by adjustment of the counterweight 45; V

Improved means is provided for steady, effective and efficient rotation of spindle 38 about'its axis in synchronism with rotation of the unit about the axis of shaft 24 (or 25), for attaining uniform deposition of article-forming material in the mold cavities. Accordingly, a fabric-reinforced, flexible rubber V-belt 4'! is engageable between a tapered annulargroove 48 of a relatively fixed sheave 49, formed integral with an outward extension 26a of bearing 26 (or21) andatapered annular groove 50 of a sheave I rotatably mounted on a stem 52 projecting from the arm 23, at the outwardly presented side thereof opposite to the spindle 38. For guiding or bending the belt 41 to have the'opposite looped ends thereof in angularly disposed planes of the fixed and rotatable sheaves 49 and 5|, respectively,

idler pulleys '52 and 53 are suitably adjustably mou-nted'at oppositesides of arm 23 at the juncture of said two planes. The spindle 33 is adapted to be rotated'on its axis, by means of a gear 54'ffixed on a reduced extension 55 of the spindle, 'meshing with a suitable gear 56 concentrically attached to the sheave 5|. In other words, if the belt 41- were connected directly to a gear' (not shown) on the spindle, the latter would b'e'driven in the same direction as the arm, and the rotative movement of the molds with the spindle would be negatived. A-suggested speed reduction between the spindle 38 and shaft 24, is approximately one revolution 'per minute of arm-23 about the axis of shaft 24 (or '25) to one and one quarter revolutions per minute of the spindle 38., In other words, when the arm 23 is rotated with shaft 24, rotative action is trans mitted to sheave 5| by thebelt 41, steadilypro gressively walking? around said fixed sheave 49. The clamping device 42 includes a' nut 58 threaded on an externally threaded boss 59, said bosshaving a central bore through which the spindle 38 is slidably receivable. A handle '60 on nut 5 8 is operable to turn the same on the threaded boss 58, axially outwardly against a split collar 6| releasably fixed 'on the spindle, thereby to urge the plate 4i inwardly to'apply requisite clamping action to the I mold stack against said plate or member 40 attached to the spindla The split collar 6! has the spindle 38 slidably received through a central aperture thereof, and is releasably clamped in fixed rela' tion to the spindle by operation of a handle62 suitably mounted and provided with cam or equivalent means to urge opposite sides of the split'portion of the collar together. As a safety feature, to prevent accidental removal of the clamping device 42 and molds 2| from the spindle, a'freely projecting end portion of spindle 38' is provided with an annular groove'64 for reception of opposed prongs of an elongated U- shaped spring clip 65 somewhat like a hairpin.

(see Figures 1 and 3.) In order to assure that the latex will reach cavity surfaces adjacent overhanging parts of the mold defining adjoining deeply recessed portions of each article-forming cavity, a suitable mechanism 66 is provided for automatically reversing the' direction of operation of power" unit 32. This may include, for eXample,-a cam -61 which is progressively engaged and rnoved by a finger 68 carried by one of the chains 33;.to operate a reversing switch (not shown) after a number of revolutions of shaft 24 in either direction.

In use of the mold-rotating apparatus, de-

' scribed above, loading and unloading of the molds 2| is accomplished while the mold-rotating units 20 are in the inoperative position best 1 shown in Figure 1, and with the safety clip 64 and clamping device 42 removed from spindle 38. For this purpose the clamping device is quickly removable. by first moving handle 62 to release the cam pressure thereof on split collar '6 I, which is then slipped off the end of the spindle. This permits removal of the plate 4| with nut 58 thereon from the spindle. {The mo1ds 2l -with articles formed thereinby a previousmold-rotating cycle, are-similarly removable one ata' time, and then replaced by molds having predetermined quantities of fiowable material, such. as latex, in each article-forming cavity thereof,'-in the same stacked relation. The new stack 22 of molds is clamped against relatively fixed plate 49, by applicationof plate 4i and collar 6 I to the spindle, as shown in Figure l, turning the handle 62 to clamp the collar fixedly on the spindle, and operating the handle 60 to'back the nut 58 on threaded boss 59 against the collar. When the mold stacks of all units 20 are thus clamped therein the power unit 32 is started to-r'otate the shafts 24 and 25, thereby swinging the. arms 23 in conical paths of movement thereof and cau's-i ing the spindles to rotate on the axes of the same.

The resultant simultaneous "rotation of the molds about angularly disposed axes insai'd pe-' riodically reversing directions,'for approximately forty-five minutes, is effective to deposit the latex bodies on the mold cavity surfaces in accreted layerings, crossing and recrossing in diverse directions of flow of the latex, until all of the'latex hasbeen so deposited in the shape of a hollow character animal A as shown in Figure 6, for 'ex* amplefof substantially accurately uniform'wall thickness. It will be noted that the moldsare not only rotated about the axes-of shafts 24"(or 25) and spindle 38, but due tomovementof'arni 23 in a conical path there is a resultanttilting of the molds above and below pivot points on the axes of said shafts 24 and 25, that is," between the angle of the molds as shown in Figure l and an extreme opposite angular position thereof when the arm 23 is in a topmost position of 'IO-' tation (not shown). Compoundrotative'move mentof the mold stacks about amultiplicity' of axes for complete uniform coverage of the mold cavities is furtherassured by automatic operation of the reversing mechanism lit.

The time required to complete the compound rotational step may vary according to conditions, such as difierences in the characteristics of the deposition material, desired thickness and size of the completed article, etc., but inactual full scale production of rubber toys of one type (see Figure 6) by the present method it has been found that latex depositionto full thickness maybe ac-. complished in approximately forty-five minutes.

The mold-rotating machine may be completely enclosed by a housing H (see Figures landZ) within which heated air from a suitable source (not shown) is circulatedaround the mold stacks 22, and between the porous molds thereon/to maintain the capillary movement of waterlfrom the latex in the respective mold cavities continu ously outward throughthe mold pores, at all times while there is either liquid or deposited latex in the molds. A suitable temperature for this air is for the present purposes approximately 90 F.

This moderately heated air, then, in circulating around the molds, including the spaces between adjacent molds, all during the pre-drying stage, will maintain the molds relatively dryer on the outside than on the inside (from the cavity surfaces), and as long as there is water in the latex deposits such water will be steadily dissipated outwardly by capillary attraction and evaporation and no wet layers or strata will be created to cause formation of recesses and holes in the articles. When succeeding latex supplies are placed in the molds the molds will again be desirably wetter inside than out and the capillary movement of the water will be maintained continuously or at least consistently outwardly as long as there is water in the latex or latex deposits.

When each article is fully formed, by deposition or accretion of latex within its mold cavity, and is ready for removal from the molds, substantially all water from the initial predetermined quantity of latex will have passed outwardly of the mold cavity by capillary attraction, through a myriad of pores in the mold material, the water being dissipated at the outer mold surfaces by evaporation.

After the articles have been fully formed and pre-dryed in the mold-rotating machine, as described above, the stacks are removed therefrom and the individual molds are opened for removal of the articles A. These articles, which may each have a relatively small whistle aperture 68 provided in the wall thereof, either during or after the rotary-casting cycle described above, are then placed on racks and vulcanized in known manner in open heat. The whistle apertures prevent the air within the articles from expanding or contracting to an extent which would cause the same to rupture or to collapse, respectively.

Although the improved apparatus has been described particularly in connection with the production of hollow rubber articles, it may be similarly utilized in the manufacture of hollow articles from other materials which are capable of flowing and drying or setting substantially in the manner described.

Modifications of the invention may be resorted to without departing from the spirit of the invention or the scope of the appended claims.

What is claimed is:

1. A machine for producing hollow articles by distribution of flowable material in article forming cavity molds comprising a support, a shaft rotatable on said support, a mold carrying arm extending radially at an angle to the axis of said shaft and rotatable therewith, a mold-supporting member mounted on said arm to rotate about an axis extending angularly of the arm and intersecting said shaft axis at an angle thereto, means for mounting at least one mold on said mold-supporting member, means for simultaneously rotating said shaft and said molding supporting member, said mold mounting means including a spindle extending therefrom for reception through apertures in the molds, a releasable clamping device for removably retaining at least one mold on the spindle, a counterweight carrying rod fixed to said mold carrying arm and extending radially from the axis of said shaft opposite said mold-supporting member and substantially parallel with said mold carrying spindle, and a counterweight carried by and movable to adjusted positions along said rod fpr adjustably counterweighting the molds on said mold carrying spindle.

2. A machine for producing hollow articles by distribution of fiowable material in an articleforming cavity mold, comprising a support, a

shaft rotatable on said support, a mold-carrying cluding an annular transmission member rotatable on said arm, an annular transmission member relatively fixed on said support concentrically with said shaft axis, a continuous flexible transmission element in driving engagement with both said rotatable and said relatively fixed transmission members, guide means on said mold-carrying element intermediate said fixed and rotatable transmission members for guiding said flexible transmission element substantially in angularly disposed planes of said fixed and rotatable transmission members, means connecting said rotatable transmission member to rotate said mold-supporting member, and means to rotate said shaft and thereby through resulting progressive walking action of said flexible transmission element on said relatively fixed transmission member to rotate said rotatable transmission member.

3. A machine as set forth in claim 2, said mold mounting means including a spindle extendingv freely therefrom for reception through an aperture in said mold, and a releasable clamping device for removably retaining at least one said mold on the spindle.

4. A machine as set forth in claim 3, said rotatable and fixed transmission members having annular tapered grooves and said flexible transmission element being a reinforced rubber V-belt engageable therein.

5. A machine as set forth in claim 1, said clamping device including a plate fixed on the spindle for backing said mold or molds received .on' said spindle, a removable plate slidably mounted on the outer end of said spindle, a split nut slidably received on said spindle outwardly of said plate, means for contracting said split nut to fix the same on the spindle, a threaded boss on said clamping plate projecting toward said split nut, and a nut threaded on said boss and rotatable thereon against said fixed split nut to urge said slidable plate into clamping engagement with said mold or molds.

DIE'I'RICH G. REMPEL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 803,799 Voelke Nov. 7, 1905 1,080,224 Latcher Dec. 2, 1913 2,222,266 Rubissow Nov. 19, 1940 2,466,277 Rubissow Apr. 5, 1949 2,469,892 Rempel May 10, 1949 

